Portable apparatus for analyzing gases



March 31, 1953 J. J. FE'RRAINOLO 2,633,411

PORTABLE APPARATUS FOR ANALYZING GASES Filed Dec. 30,19502.$l-1EE'I'SSl-IEET '1 March 31, 1953 J. J. FERRAINOLO PORTABLEAPPARATUS FOR ANALYZING GASES 2 SHEETS-SHEET -2 Filed Dec. 30, 1950attorney Patented Mar. 31, 1953 UNITED STATES PATENT OFFICE PORTABLEAPPARATUS FOR ANALYZING GASES Joseph J. 'Ferrainolo, Pittsburgh, Pa.Application December 30, 1'950,Serial No. 203,665

11 Claims.

This invention relates to gas analyzers, and particularly to a portabletype of analyzer of simplified construction and operation which isextremely accurate, permits spot analysis, eliminates manifold, doesaway with the use'of measuring burettes and interconnected absorptionbulbs.

There have been many types of apparatus and many methods proposed forthe rapid analysis of gases, particularly mine gases where it isimportant that the composition of thegases in the mine atmosphere beconstantly checked to avoid the formation "of dangerous explosivemixture or the failure of the oxygen supply or its replacement by deadlyand noxious gases. Typical of the standard apparatus used is the Orsatanalyzer in which a measured amount of gas is drawn into a calibratedburette and then passed successively through absorbing solutions forremoving each constituent separately. After passing through any one ofthe absorbing solutions the remaining gas is returned to the burette andmeasured before being passed to the next absorbing solution. It is atonce -apparent that such an apparatus and method requires considerabletime in order to make the various passes in the successive absorbingsolutions and the necessary measurements after each. The Orsat type ofapparatus has been modified in various ways in order to make it portableand to simplify its operation. Such a modification is that shown in thepatent to Bailey, Number 2,448,206, issued August 31, 1948. However,these modifications have not done away with the need for a calibratedburette and the successive passes through the absorbing solutions andsucceeding returns to the burette for measurement. Moreover, the Orsattype of apparatus by reason of its design requires the use of many stopcocks, which must be greased often to work smoothly.

According to this invention there is provided an apparatus and method ofgas analysis by means of which these undesirable characteristics of thepresent day gas analyzers are avoided. According to the apparatus ofthis invention the need for a carefully calibrated burette is avoided,the multiplicity of absorbing passes in various solutions and return tothe burette for reading are avoided. In addition the need for line cocksis avoided and thereby the concomitant troubles arising therefrom.

The apparatus of the invention comprises genorally at least onemeasuring compartment, a corresponding absorbing compartment for eachmeasuring compartment connected thereto by a one way valve, saidabsorbing compartment be- .2 ing open at the top thereof, a separateleveling means connected to the bottom of each absorbing compartment,means in said absorbing compartment for reacting and removing knowncomponentsof the -gas,a piston in each measuring compartment forcing agas collected in the measuring compartment through the-one way valveinto the corresponding absorbing compartment, a similar piston inthe'open end of the absorbing compartment retaining the residue-gas inthe absorbing compartment, an exhaust means intermediate the ends of theabsorbing compartment through which the gas remaining at the end of ananalysis can be removed, a compensator piston and chamber'of the samesize as the measuring compartment, said chamber being closed at thebottom and open at the top, whereby the effects of changes of barometricpressure and temperature can be compensated for, and measuring meansadjacent each of theabsorbing chamber and the compensator chamberwhereby changes in volume can be measured.

In a preferred form of apparatus there is provided three measuringchambers and three absorbing chambers for determining CH4, CO2, and O2in the gas being "analyzed. The measuring chamber and absorbing chamberare preferably in a single glass cylinder divided intermediate its endsto form two cylindrical chambers closed at one end.

The operation and. construction of the structure of this invention willbe more clearly and easily understood by referring to the drawings inwhich:

Figure 1 is a'front elevation with the front of the cylinders cut awayshowing the apparatus of this invention.

Figure 2 is a side elevation of the apparatus of Figure 1.

Figure 3 is an enlarged front elevation of the absorbing chamber pistonand measuring means.

Figure 4 is a section on the line 4-4 of Figure 3.

Figure 5 is an enlarged side elevation of the absorbing chamber pistonand measuring means.

Figure 6 is an enlarged front elevation of the leveling bottle and bulbused in the preferred form of apparatus.

Figure '7 is an enlarged elevation of a piston as used in the measuring,the absorbing and the compensating chambers.

Figure 8 is an enlarged elevation of the one way valve of thisinvention.

Figure 9 is a section through the exhaustmember showing it in openposition.

Figure is a section through the exhaust member showing it in closedposition.

Referring to Figure 1 there is illustrated a portable gas analyzerhaving a frame I 0 upon which are fixed supporting legs H and a carryinghandle 12. Mounted on the frame are three cylinders l3, l4, and I5, eachone divided into two compartments by a division wall l6 intermediatetheir ends. These chambers are a measuring chamber '39., Ma, and a. offixed volume at the bottom and an absorbing chamber i311, Mb, and 85b atthe top. A one way valve I1 is provided in the wall It to carry the gasfrom the measuring chamber to the corresponding absorbing chamber. Thevalve i! is provided with a screen covering [8, preferably of platinumfor breaking up the gas into myriads of small bubbles which pass throughthe absorbing liquid in the absorbing chamber. A spiral glass baffle .l9is provided in all absorbing chambers in which combustion does not takeplace. These are for the purpose of causing the gas bubbles to be incontact with the absorbing liquid for a longer period of time to promotebetter absorption. A resistance wire or heating element is provided .inthe chamber where combustion is to take place; this wire is energized bya battery 2| mounted on the back of the frame it through a switch 22mounted on the frame It. A piston 23 is provided in each of themeasuring chambers to force the gas from that chamber to the absorbingchamber. A second piston 28, made in such form as to reduce its weight,is provided in the open end of the absorbing chamber. Each .of the upperpistons 24 is provided with a knurled handle for ease of handling whenoperating the device. Each of the absorbing chambers is pro- ;vided withan exhaust outlet made up of a glass side arm 25 fixed to the chamber, ashort sec .tion of flexible tube 26 which is adapted to be pinchedtogether by a clamp 21 and a terminal section of glass tubing 28;preferably bent upward at an angle from the line of the side arm 25. Asecond side arm '29 is provided at the bottom of each absorbing member.To this side arm, which also serves as a bubble trap, due to thedownward bend of the outlet to the reservoir, is attached a flexibletube 30 which terminates in a reservoir or leveling bottle 3|. Theleveling ,bottle is held to the frame by a clamp 32 from which it may beloosened to raise and lower it. A stopper 33 fitted with a glass tube 34and a flexible tube 35' and rubber expansion bag 38 is provided in theopen end of the leveling bottle 3 I.

At the side of each absorbing chamber there is provided a micrometermeasuring scale 31. The bottom nib 38 is used as the base level fromwhich computations are made, and the moving nib 39 (see Figure 4) isadjusted to the upper limit of the gas in the absorbing chamber, bothnibs are provided with a fork-like element or marker, as shown.

A compensator 40 is provided to correct for changes in barometricpressure and temperature. The compensator consists of a chamber 4|having the same dimensions as the measuring chamber of the cylnders l3,l4, and I5 and fitted with a piston 24 identical with the upper pistons24 in the absorbing chamber of cylinder 13. A micrometer scale 31 isprovided on the compensator chamber 41 as on the absorbing chamber, thelower nib 38 of the micrometer being set at the level of the bottom ofthe interior of the com- 'pensator chamber 4 I.

In using the apparatus, it is taken to the spot from which an analysisis desired, the pistons 23 are removed from the measuring chambers I35,its, and l5a. These chambers fill up with the gases from the surroundingatmosphere and the pistons 23 are reinserted trapping a fixed volume ofgas in the chambers. The pistons are forced into the measuring chamberthereby forcing the gases through the one Way valves H into theabsorbing chamber where they bubble through the solutions maintainedtherein. In the case of CO2 gas an alkaline solution such as potassiumhydroxide is used in the absorbing chamber and in the case of 02 gas asolution of potassium pyrogallate is used. These are well known andrecognized absorbents for such gases. When CO2 and O2 bubble through theabsorbing solutions they are absorbed and the gas which reaches the topof the solution is free of the gas being absorbed. The gas which reachesthe top of the solution forces the pistons 24 at the top of theabsorbing chamber to rise. The amount of movement of this pistondetermines the amount of the gas which has been absorbed in thesolution. In the case of either CO2 or 02 the leveling bulb 3! is movedto bring the solution level to the level of the lower nib marker 38 ofthe micrometer scale. The upper nib marker 33 of the micrometer is nextmoved to the bottom of the piston 24 and the distance between the nibmarkers gives the amount of gas unreacted or unabsorbed.

At the time the measuring chambers are filled. the compensator chamberil may also be filled by removing the piston 24 and replacing it. Whenthe micrometer reading of the absorbing chamber is taken, a like readingof the compensator chamber is taken. This reading corrects for anychanges in the barometric pressure or temperature since it is of fixedvolume. The reading from the absorption chamber is subtracted from thecompensator chamber reading to give the amount of gas absorbed. Theresult is then divided by the total compensator reading and multipliedby hundred. In the case of CO2 this gives the percentage of CO2 in thegas. In the case of 02 the percent of CO2 must be subtracted from thefinal result since alkaline pyrogallate absorbs both 02 and CO2.

Where an analysis of the methane (CH4) content of the gas is desired,the gas is forced above the solution in absorbing chamber l5b as in thecase-of CO2 and Oz. The solution level is lowered by means of theleveling bottle until the burning wire or ignitor 2%! is exposed. Thecurrent is turned on and the wire becomes hot causing the methane toburn. The solution is raised and lowered below the wire several times inorder to assure complete combustion. The current is turned on and thereading made as in the case of CO2 and C2. The resulting percentage mustbe divided by two to get the percent of methane. This is because twovolumes of gas are destroyed for each volume of methane according to thefollowing reaction:

CH4+2O2=CO2+2H2O (gas) (gas) (gas) (liquid) When the analysis iscompleted the absorbing chambers are cleared of remaining gases by firstlowering the level of the liquid below the exhaust outlet by loweringthe reservoir, after which the clamp 21 is opened thereby permitting thegas to escape from the side arm or exhaust outlet 25, flexible tube 26and elbow 28. Any gas between the level of the liquid and the bottom ofthe piston is forced through the exhaust outlet 25 by manually pressingthe piston 24 downwardly.

The simplicity and ease of operation of the apparatus of this inventionis believed to be readily apparent and the many advantages to be gainedby its use need not be outlined here. It should be noted, however, thatby using this apparatus it is possible to analyze gases rapidly at thepoint where they are taken without elaborate equipment and loss of time.

It will be understood that the apparatus of this invention may takedifferent forms depending upon the conditions under which it is to beused within the terms of the following claims.

I claim:

"1. A portable apparatus for analyzing gases comprising at least onemeasuring compartment, a corresponding absorbing compartment for eachmeasuring compartment, said measuring compartment-and absorbingcompartment being=connected by a one way valve, said absorbingcompartment being open at the top thereof, a separate leveling meansconnected to the bottom of each absorbing compartment, said absorbingcompartment being adapted to contain aselective liquid absorbentremoving known components of a gas, a piston in each measuringcompartment forcing a gas collected in the measuring compartment throughthe one way valve into the corresponding absorbing compartment, a secondpiston in the open end of the absorbing compartment retaining theresidue gas in the absorbing compartment, an exhaust means intermediatethe ends of the absorbing compartment through which the gas remaining atthe end of an analysis can be removed, a compensator piston and chamberof the same size as the measuring compartment, said chamber being closedat the bottom and open at the top whereby the effects of barometricpressure and temperature can be compensated for, and measuring meansadjacent each of the absorbing chamber and the compensator chamberwhereby changes in volume can be measured.

2. A portable apparatus for analyzing gases comprising at least one rneasuring compartment, a corresponding absorbing compartment for eachmeasuring compartment, said measuring compartment and absorbingcompartment being connected by a one way valve, a screen mesh coveringthe discharge end of said valve whereby the gases passing therethroughare broken up into smaller bubbles, said absorbing chamber being open atthe top thereof and fitted with a movable piston, said measuringcompartment being open at the end opposite its connection with theabsorbing compartment and fitted with a movable piston, a separateleveling means connected to the bottom of each absorbing compartment,said absorbing compartment being adapted to contain a selective liquidabsorbent removing known components of a gas, an exhaust meansintermediate the ends of the absorbing compartment through which the gasremaining at the end of an analysis can be removed, a compensator pistonand chamber having the same size as the measuring compartment, saidchamber being closed at the bottom and open at the top whereby theefiects of barometric pressure and temperature can be evaluated, andmeasuring means adjacent each of the absorbing chamber and thecompensator chamber whereby changes in volume can be measured.

3. A portable apparatus for analyzing gases comprising a frame, at leastone cylindrical tube Cit open at both ends mounted on saidframe in avertical position, a wall intermediate the ends of said tube containinga "one way valve, said wall and tube defining a lower measuring com--partment and an upper "absorbing compartment, leveling means connectedto the absorbing compartment adjacent the wall, said absorbingcompartment being adapted to contain a selective liquid absorbentremoving known components of a gas therein, a piston in each measuringcom partment forcing a gascollected therein through the one way valveinto the absorbing compart ment, a piston slidable in the 'open end "ofthe absorbing compartment retaining the gas which enters the absorbingcompartment, exhaust means intermediate the ends of the absorbincompartment through which the gas remaining at the end of an analysiscan be removed, a compensator piston and chamber of the same size as the'measuringcompartment, said chamber being closed at the bottom and openat the top whereby the efiects of barometric pressure and temperaturecan be compensated for, and measuring means adjacent each of theabsorbing compartment and the compensator chamber whereby changes involume can be measured.

4. A portable apparatus for analyzing gases as claimed in claim 3 inwhich the measuring means include a hired base point adjacent to andintermediate the ends of the absorbing compartment, a movable indexmember slidable vertically along the absorbing compartment above thebase point and micrometer screw means attached to the inde'ii member formoving it -'along the wail of the absorbing compartment.

5. A portable apparatus for analyzing gases as claimed in claim 3 inwhich the one way valve is provided with a screen mesh covering theoutlet end thereof whereby the gasses passing through the valve arebroken up into a large number of small bubbles. v

6. A portable apparatus for analyzing gases comprising a frame, aplurality of cylindrical tubes open at both ends thereof mountedvertically on the frame at spaced apart positions, a wall intermediatethe ends of each of said tubes containing a one way valve, said wall andtube defining a lower measuring compartment and an upper absorbingcompartment, leveling means connected to the absorbing compartmentadjacent the wall, a manually operable piston in each measuringcompartment forcing a gas collected therein through the one way valveinto the absorbing compartment, 3, piston slidable in the open end ofthe absorbing compartment retaining the gas which enters the absorbingcompartment, exhaust means intermediate the ends of the absorbingcompartment through which the gas remaining at the end of an analysismay be removed, electrical ignition means in one absorbing compartmentof said plurality of tubes, connections from the ignition means to asource of electrical energy for actuating the ignition means, theremaining absorbing compartments of said plurality of tubes beingadapted -to contain a selective liquid absorbent removing knowncomponents of gas therein, a compensator piston of the same size as thepiston in each absorbing compartment, a compensator chamber of the samesize as the measuring compartment receiving said compensator piston,said-chamber being closed at the bottom and open'at the topwhereb'y theeffects of barometric pressure and temperature can be compensated for,and measuring means adjacent each of the absorbing compartment and thecompensator chamber whereby changes in volume can be measured. 7. Aportable apparatus for analyzing gases as claimed in claim 6 in whichthe absorbing chambers other than that one provided with the ignitionmeans are provided with a glass vertical spiral extending from a pointabove the intermediate wall but below the exhaust means. 8. A portableapparatus for analyzing gases comprising at least one measuringcompartment, a corresponding absorbin compartment for each measuringcompartment, said measuring compartment and absorbing compartment beingcon nected by a one way valve, 2, screen mesh covering the discharge endof said valve whereby the gases passingv therethrough are broken up intosmaller bubbles, said absorbing chamber being open at the top thereofand fitted with a movable piston, said measuring compartment being openat the end opposite its connection with the absorbing compartment andfitted with a movable piston, a separate leveling means connected to thebottom of each absorbing compartment, said leveling means includin adownwardly bent side arm at the bottom of the absorbing compartmentadapted to serve as a bubble trap, a flexible tube connected to saidside arm, and a reservoir bottle connected to the flexible tube, saidreservoir bottle adapted to maintain the liquid at the surroundingatmospheric pressure, said absorbing compartment being adapted tocontain a selective liquid absorbent removing known components of a gas,an exhaust means intermediate the ends of the absorbing compartmentthrough which the gas remaining at the end of an analysis can beremoved, a oom pensator piston and chamber having the same size as themeasuring compartment, said chamber being closed at the bottom and openat the top whereby the effects of barometric pressure and temperaturecan be evaluated, and measurin means adjacent each of the absorbingchamber and the compensator chamber whereby changes in volume can bemeasured.

9. A portable apparatus for analyzing ases comprising a frame, at leastone cylindrical tube open at both ends mounted on said frame in avertical position, a wall intermediate the ends of said tube containinga one way valve, said wall and tube defining a lower measuringcompartment and an upper absorbing compartment, leveling means connectedto the absorbing compartment adjacent the wall, said leveling meansincluding a downwardly bent side arm at the bottom of the absorbingcompartment adapted to serve as a bubble trap, a flexible tube connectedto said side arm and a reservoir bottle connected to the flexible tube,:said reservoir bottle adapted to maintain the liquid at the surroundingatmospheric pressure, said absorbing compartment being adapted tocontain a selective liquid absorbent removing known components of a gastherein, a piston in each measuring compartment forcing a gas collectedtherein through the one way valve into the absorbing compartment, apiston slidable in the open end of the absorbing compartment retainingthe gas which enters the absorbing compartment, exhaust meansintermediate the end of the absorbing compartment through which the gasremaining at the end of an analysis can be removed, a compensator pistonand chamber of the same size as the measuring compartment,

said chamber being closed at the bottom and open at the top whereby theeffect of barometric pressure and temperature can be compensated for,and measuring means adjacent each of the absorbing compartment and thecompensator chamber whereby changes in volume can be measured.

10. In portable apparatus for analyzing gases a measuring and absorbingdevice comprising a measuring compartment, a corresponding absorbingcompartment, said measuring compartment and absorbing compartment beingconnected by a one way valve, a screen mesh covering the discharge endof said valve whereby the gases passing therethrough are broken up intosmaller bubbles, said absorbing chamber being open at the top thereofand fitted with a movable piston, said measuring compartment being openat the end opposite its connection with the absorbing compartment andfitted with a movable piston, leveling means connected to the bottom ofthe absorbin compartment, said absorbing compartment being adapted tocontain a selective liquid absorbent removing known components of a gasand exhaust means intermediate the ends of the absorbing compartmentthrough which the gas remaining at the end of an analysis can beremoved. 11. In portable apparatus for analyzing gases a measuring andabsorbing device comprising a measuring compartment, a correspondingabsorb.. ing compartment, said measuring compartment and absorbingcompartment bein connected by a one way valve, a screen mesh coveringthe discharge end of said valve whereby the gases passing therethroughare broken up into smaller bubbles, said absorbing chamber being open atthe top thereof and fitted with a movable piston, said measuringcompartment being open at its end opposite its connection with theabsorbing compartment and fitted with a movable piston, leveling meansconnected to the bottom of the absorbing compartment, said levelingmeans including a downwardly bent side arm at the bottom of theabsorbing compartment adapted to serve as a bubble trap, a flexible tubeconnected to said side arm, and a reservoir bottle connected to theflexible tube, said reservoir bottle adapted to maintain the liquid atthe surrounding atmospheric pressure, said absorbing compartment beingadapted to contain a selective liquid absorbent removing knowncomponents of a gas and exhaust means intermediate the ends of theabsorbing compartment through which the gas remaining at the end of ananalysis can be removed.

JOSEPH J. FERRAINOLO.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 489,117 Great Britain July 10, 1938

10. IN PORTABLE APPARATUS FOR ANALYZING GASES A MEASURING AND ABSORBINGDEVICE COMPRISING A MEASURING COMPARTMENT, A CORRESPONDING ABSORBINGCOMPARTMENT, SAID MEASURING COMPARTMENT AND ABSORBING COMPARTMENT BEINGCONNECTED BY A ONE WAY VALVE, A SCREEN MESH COVERING THE DISCHARGE ENDOF SAID VALVE WHEREBY THE GASES PASSING THERETHROUGH ARE BROKEN UP INTOSMALLER BUBBLES, SAID ABSORBING CHAMBER BEING OPEN AT THE TOP THEREOFAND FITTED WITH A MOVABLE PISTON, SAID MEASURING COMPARTMENT BEING OPENAT THE END OPPOSITE ITS CONNECTION WITH THE ABSORBING COMPARTMENT ANDFITTED WITH A MOVABLE PISTON, LEVELING MEANS CONNECTED TO THE BOTTOM OFTHE ABSORBING COMPARTMENT, SAID ABSORBING COMPARTMENT BEING ADAPTED TOCONTAIN A SELECTIVE LIQUID ABSORBENT REMOVING KNOWN COMPONENTS OF A GASAND EXHAUST MEANS INTERMEDIATE THE ENDS OF THE ABSORBING COMPARTMENTTHROUGH WHICH THE GAS REMAINING AT THE END OF AN ANALYSIS CAN BEREMOVED.